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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.feilong.lib.lang3;
import java.util.Locale;
/**
*
* Operations to assist when working with a {@link Locale}.
*
*
*
* This class tries to handle {@code null} input gracefully.
* An exception will not be thrown for a {@code null} input.
* Each method documents its behaviour in more detail.
*
*
* @since 2.2
*/
public class LocaleUtils{
private static final String EMPTY = "";
//-----------------------------------------------------------------------
/**
*
* Converts a String to a Locale.
*
*
*
* This method takes the string format of a locale and creates the
* locale object from it.
*
*
*
* LocaleUtils.toLocale("") = new Locale("", "")
* LocaleUtils.toLocale("en") = new Locale("en", "")
* LocaleUtils.toLocale("en_GB") = new Locale("en", "GB")
* LocaleUtils.toLocale("en_001") = new Locale("en", "001")
* LocaleUtils.toLocale("en_GB_xxx") = new Locale("en", "GB", "xxx") (#)
*
*
*
* (#) The behaviour of the JDK variant constructor changed between JDK1.3 and JDK1.4.
* In JDK1.3, the constructor upper cases the variant, in JDK1.4, it doesn't.
* Thus, the result from getVariant() may vary depending on your JDK.
*
*
*
* This method validates the input strictly.
* The language code must be lowercase.
* The country code must be uppercase.
* The separator must be an underscore.
* The length must be correct.
*
*
* @param str
* the locale String to convert, null returns null
* @return a Locale, null if null input
* @throws IllegalArgumentException
* if the string is an invalid format
* @see Locale#forLanguageTag(String)
*/
public static Locale toLocale(final String str){
if (str == null){
return null;
}
if (str.isEmpty()){ // LANG-941 - JDK 8 introduced an empty locale where all fields are blank
return new Locale(EMPTY, EMPTY);
}
if (str.contains("#")){ // LANG-879 - Cannot handle Java 7 script & extensions
throw new IllegalArgumentException("Invalid locale format: " + str);
}
final int len = str.length();
if (len < 2){
throw new IllegalArgumentException("Invalid locale format: " + str);
}
final char ch0 = str.charAt(0);
if (ch0 == '_'){
if (len < 3){
throw new IllegalArgumentException("Invalid locale format: " + str);
}
final char ch1 = str.charAt(1);
final char ch2 = str.charAt(2);
if (!Character.isUpperCase(ch1) || !Character.isUpperCase(ch2)){
throw new IllegalArgumentException("Invalid locale format: " + str);
}
if (len == 3){
return new Locale(EMPTY, str.substring(1, 3));
}
if (len < 5){
throw new IllegalArgumentException("Invalid locale format: " + str);
}
if (str.charAt(3) != '_'){
throw new IllegalArgumentException("Invalid locale format: " + str);
}
return new Locale(EMPTY, str.substring(1, 3), str.substring(4));
}
return parseLocale(str);
}
/**
* Tries to parse a locale from the given String.
*
* @param str
* the String to parse a locale from.
* @return a Locale instance parsed from the given String.
* @throws IllegalArgumentException
* if the given String can not be parsed.
*/
private static Locale parseLocale(final String str){
if (isISO639LanguageCode(str)){
return new Locale(str);
}
final String[] segments = str.split("_", -1);
final String language = segments[0];
if (segments.length == 2){
final String country = segments[1];
if (isISO639LanguageCode(language) && isISO3166CountryCode(country) || isNumericAreaCode(country)){
return new Locale(language, country);
}
}else if (segments.length == 3){
final String country = segments[1];
final String variant = segments[2];
if (isISO639LanguageCode(language) && (country.isEmpty() || isISO3166CountryCode(country) || isNumericAreaCode(country))
&& !variant.isEmpty()){
return new Locale(language, country, variant);
}
}
throw new IllegalArgumentException("Invalid locale format: " + str);
}
/**
* Checks whether the given String is a ISO 639 compliant language code.
*
* @param str
* the String to check.
* @return true, if the given String is a ISO 639 compliant language code.
*/
private static boolean isISO639LanguageCode(final String str){
return StringUtils.isAllLowerCase(str) && (str.length() == 2 || str.length() == 3);
}
/**
* Checks whether the given String is a ISO 3166 alpha-2 country code.
*
* @param str
* the String to check
* @return true, is the given String is a ISO 3166 compliant country code.
*/
private static boolean isISO3166CountryCode(final String str){
return StringUtils.isAllUpperCase(str) && str.length() == 2;
}
/**
* Checks whether the given String is a UN M.49 numeric area code.
*
* @param str
* the String to check
* @return true, is the given String is a UN M.49 numeric area code.
*/
private static boolean isNumericAreaCode(final String str){
return StringUtils.isNumeric(str) && str.length() == 3;
}
}